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Fixed PPU even_odd_timing test (when disabling BG just before cycle 339)

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This commit is contained in:
Souryo 2016-01-02 18:02:56 -05:00
parent eec6bc8f77
commit 5f2d2851fe
2 changed files with 11 additions and 1 deletions
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11
Core/PPU.cpp
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@ -31,6 +31,8 @@ PPU::~PPU()
void PPU::Reset()
{
_skipTick = false;
_state = {};
_flags = {};
_statusFlags = {};
@ -536,11 +538,16 @@ void PPU::ProcessPrerenderScanline()
//copy vertical scrolling value from t
_state.VideoRamAddr = (_state.VideoRamAddr & ~0x7BE0) | (_state.TmpVideoRamAddr & 0x7BE0);
}
} else if(_nesModel == NesModel::NTSC && _cycle == 339 && IsRenderingEnabled() && (_frameCount & 0x01)) {
} else if(_nesModel == NesModel::NTSC && _cycle == 338 && IsRenderingEnabled() && (_frameCount & 0x01)) {
//Check for the cycle skip in the else if block below
//If, at cycle 338 in the prerender scanline, rendering is enabled, we skip a tick (cycle 340) on the current frame
_skipTick = true;
} else if(_cycle == 339 && _skipTick) {
//This behavior is NTSC-specific - PAL frames are always the same number of cycles
//"With rendering enabled, each odd PPU frame is one PPU clock shorter than normal" (skip from 339 to 0, going over 340)
_cycle = -1;
_scanline = 0;
_skipTick = false;
} else if(_cycle == 321 || _cycle == 329) {
LoadTileInfo();
if(_cycle == 329) {
@ -785,6 +792,8 @@ void PPU::StreamState(bool saving)
Stream<uint16_t>(_spriteDmaAddr);
Stream<uint16_t>(_spriteDmaCounter);
Stream<bool>(_skipTick);
if(!saving) {
SetNesModel(_nesModel);
}

1
Core/PPU.h
View File

@ -110,6 +110,7 @@ class PPU : public IMemoryHandler, public Snapshotable
NesModel _nesModel;
uint16_t _vblankEnd;
bool _skipTick;
PPUControlFlags _flags;
PPUStatusFlags _statusFlags;